中文摘要：

草坪是城市绿地系统的重要组成部分,为量化其在城市碳平衡中的作用,采用静态箱-气相色谱法对上海结缕草草坪CO2排放通量进行了研究。结果表明：CO2排放通量具有明显的日变化和季节变化特征,日变化表现为昼高夜低的特点,最大排放通量一般出现在正午前后,最小在清晨,最大日较差为1 187.7mg/（m2.h）（7月1日）,最小89.2mg/（m2.h）（1月3日）。CO2排放通量的季节变化呈单峰型,夏季7月最大,春秋季次之,冬季1月最小,与温度的季节变化一致。观测期间年平均CO2排放通量为619.4mg/（m2.h）。对上海城市结缕草草坪观测期间,温度是CO2排放通量变化的主要影响因素。研究成果不仅可为城市草坪碳排放提供基础数据,也可为城市碳循环研究和管理提供参考。

英文摘要：

Urban lawn,as the main part of urban green land,plays very important role in regulating the carbon balance in city.The characteristics of CO2 emission flux over an urban lawn ecosystem in Shanghai were studied with the static closed chamber sampling technique and gas chromatograph analysis.The results showed that CO2 emission flux exhibited an obvious diurnal and seasonal variation.The daily maximum values appeared at about noon when the temperature was highest,while the daily minimum values appeared at night or dawn when the temperature was lowest.The maximum daily variation range was 1 187.6 mg /（m2·h）（1st July）,and the minimum one was 89.2 mg /（m2·h）（3rd Jan.）.The seasonal variation of the flux showed the maximum value in summer and the minimum one in winter,which was caused by temperature and plant growth.During the observation period,the annual average value CO2 flux was 619.4 mg /（m2·h）.Temperature was the main factor influencing the CO2 flux in the studied lawn,while soil moisture seemed not a significant factor.The results provide the basic data of CO2 flux in urban lawn,which can contribute to the study and management of carbon cycle in the city.